Gas analysis pipettes



Patented July 20, 1954 UNITED STATES PATENT OFFICE GAS ANALYSIS PIPETTESLloyd V. Guild, LibrarmPa.

Application August 10, 1949, Serial No. 109,436

2 Claims. 1

This invention relates to improvements in gas analysis pipettes f thebubbler type for use in the Orsat method of gas analysis, and it isamong the. objects thereof to provide a pipette structure utilizing aminimum volume of gas to displace the liquid from the valve system,whereby the analyses may be made by a single pass of the gas through thesolution.

It is a further object of the invention to provide a bubbler pipetteconstruction which will retain a minimum amount of the liquid in thevalve system to prevent drawing part of the absorption solution into thegas measuring tube.

The invention will become more apparent from a consideration of theaccompanying drawing, constituting a part hereof, in which likereference characters designate like parts, and in which:

Fig. l is a front elevational view of a gas analysis pipette embodyingthe principles of this invention;

Fig. 2 a front elevational view of a modified form of gas analysispipette; and

Fig. 3 an enlarged fragmentary portion of the valve system of thepipette, as will be hereinafter explained.

With reference to the several figures of the drawing, numeral Idesignates a container usually made of glass which may have a reentrantbottom 2 and. is sealed at the base, the reentrant bottom being ofconical shape to be self-centering upon a complementary shaped seat (notshown) on a pipette support. The container I has an opening or neck 3 bywhich it is charged with a reagent liquid capable of absorbing specificgaseous components from a mixture of gas, and the volume change in thegas after passing through the reagent is the basis for calculating theanalysis of that component.

Container l is provided with a cylindrical inner wall 4 which is sealedto the outer wall I at 5, the top of the container l terminating in asloping wall 6 and a reduced portion 1 that forms a valve chamberdesignated by the numeral 8. The restricted portion I terminates in acapillary tube 9 which is connected by a, rubber hose, or otherwise, toa source of gas to be analyzed. The chamber constituted by thecylindrical partition wall 4 and designated by the reference characterII), is the bubbling chamber which is separated from the valve chamber 8by a partition ll having a passage l2 which is a drilled or punched holein axial alignment with the passage 13 of the capillary tube 9 so as tobe in central register therewith.

As shown in the enlarged view of Fig. 3, the

partition H has its upper Wall sloping, as designated by the numerall3a, and a ball valve l4, of glass or other suitable material, centerson the opening l2 but is capable of being displaced as shown by thedotted position of the ball valve l 4. The top edge of the passage I2 ispreferably sharp to provide a minimum seating surface for the ball I4.Chamber 8 is also provided with a flow passage l5 comunicating with atube l6 that is the bubbler tube terminating in a spherical end I!having perforations it through which the gas escapes into the absorptionchamber I0.

In the form of the device shown in Fig. 2, the absorption tube 19 isseparated from the storage container 20 and is connected thereto by atube 2|. The neck I, the capillary tube 9, the valve chamber 8, and theball valve [4 with the partition II and passages 12 and I5 are the sameas described in connection with Fig. 1 of the drawing.

In the use of either of the devices shown in Figs. 1 and 2, the liquidabsorbent is poured through the openings 3 and is drawn up to above thevalve chamber 8 to a level within the capillary flow passage l3. Theinner chamber or absorption chamber In is thus full of liquid and theouter chamber to about the level shown at 22. In filling the chamber Illthe ball valve I4 is unseated and the bubbler tube [6 is also full ofliquid.

When gas is forced into the pipette through the passage [3, the glassbal1 I4 seals off the inlet 12 and the gas is forced through bubblertube I6 and through the orifices [8 into the absorption chamber. As thegas bubbles from the spherical end I! through the reagent solution, itwill accumulate at the top of the cylindrical chamber I!) but will notunseat the valve I4 because the pressure differential is such that thepressure of the incoming gas through the capillary passage l3 retainsthe ball valve 14 on the seat of the opening [2.

When the charging pressure of the gas is released, valve M will unseatand the accumulated gases in absorption chamber It will escape throughpassage [2 and the volume change is noted. Since the tapered seat l3a ofthe ball valve i4 is ground at an angle which is approximately 8 fromthe horizontal, a sharp seal is effected between the ball and theopening, the slight slope acting to maintain the ball in its properposition. It is evident that no liquid remains in the valve chamber 8and that the volume of said chamber is relatively small. Thereforeaccurate measurements of the gas volumes may be made. Also by sealingoff the top of the inner cylindrical wall 4, there is no danger of aircontamination as where a large area of the outer vessel is open to theatmosphere.

Since no liquid can be trapped in the valve system, no gas is requiredto displace liquid from the valve chamber and complete absorption may beeffected by a single pass of the gas through the pipette.

Although one embodiment of the invention has been herein illustrated anddescribed, it will be evident to those skilled in the art that variousmodifications may be made in the details of construction withoutdeparting from the principles herein set forth.

I claim:

1. In a gas analysis pipette, a container having a bubbler tubeextending to adjacent the bottom thereof with perforations at the bottomof the tube, said tube terminating in a valve chamber, means forsupplying a reagent solution to said container other than through thebubbler tube passage, a, capillary connection from a source of gas tosaid valve chamber, the valve chamber having a horizontal partition withan opening in register with the center of the capillary tube, and a ballvalve supported by said partition for sealing said passage, saidpartition having a ground tapered surface for centering the ball valvewith the valve opening.

2. In a gas analysis pipette, a pair of containers having acommunicating passage at the bottom of said containers, a bubbler tubeextending to adjacent the bottom of one of said containers withperforations at the bottom of the tube, said tube terminating in a valvechamber at the top of the container, means for supplying a reagentsolution through an opening in the other of said containers, a capillaryconnection from a source of gas to said valve chamber, the valve chamberhaving a horizontal partition with an opening in register with thecenter of the capillary tube, and a ball valve supported by saidpartition for sealing said passage, said partition having a groundtapered surface for centering the ball valve with the valve opening.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,001,581 Matuszak May 14, 1935 FOREIGN PATENTS Number CountryDate 608,322 France Apr. 19, 1926 37,810 France Nov. 18, 1980 (1staddition to 608,322)

OTHER REFERENCES Matuszak; Fisher Gas Analysis Manual,

Fisher Scientific 00., Pittsburgh, Pa., pages 54, 55. Copyright 1934.

1. IN A GAS ANALYSIS PIPETTE, A CONTAINER HAVING A BUBBLER TUBEEXTENDING TO ADJACENT THE BOTTOM THEREOF WITH PERFORATIONS, AT THEBOTTOM OF THE TUBE, SAID TUBE TERMINATING IN A VALVE CHAMBER, MEANS FORSUPPLYING A REAGENT SOLUTION TO SAID CONTAINER OTHER THAN THROUGH THEBUBBLER TUBE PASSAGE, A CAPILLARY CONNECTION FROM A SOURCE OF GAS TOSAID VALVE CHAMBER, THE VALVE CHAMBER HAVING A HORIZONTAL PARTITION WITHAN OPENING IN REGISTER WITH THE CENTER OF THE CAPILLARY TUBE, AND A BALLVALVE SUPPORTED BY SAID PARTITION FOR SEALING SAID PASSAGE, SAIDPARTITION HAVING A GROUND